In order to receive or transmit a still image from or over a distance, a facsimile machine is provided with an image analysis unit, an image restitution unit, generally a printer, an image signal processing unit and an image signal transmission and reception unit.
An image analyzer (scanner), designed to translate visual information contained in the image into electrical signals, comprises a sensor and an image illuminating system, such as a fluorescent tube or a linear array of light-emitting diodes (LEDs).
The image sensor may be produced using:
either a linear array of photosensors, charge transfer phototransistors also known as CCDs (Charge Coupled Devices), for example, associated with a focusing lens, and designed to analyze the illuminated image line by line as it is moved, PA1 or a linear array of photosensors on the scale of* a CIS (Contact Image Sensor), also designed to analyze the illuminated image as it is moved.
In order to transmit the image data which has been analyzed in this way, the photosensors are associated with analog shift registers.
The printer, more particularly a laser printer, is provided with a system for laser illumination of a photosensitive print drum, with the illuminating system comprising either a linear array of light-emitting diodes (LEDs), or one light-emitting diode which is associated with mechanical means for optical scanning, using a revolving mirror for example.
The revolving mirror, linear arrays of photosensors, focusing lens, analog shift registers and linear arrays of light-emitting diodes are costly elements of the image analyzer and the laser printer, and this increases the cost of the facsimile machine.
Items of office equipment with image analyzers and printers are known wherein the analyzing and printing scans are both carried out by means of a single laser emitting source.
Thus, in EP-A-0 028 845, the laser beam emitted by the single source is split into two beams, for printing and analysis respectively.
In U.S. Pat. No. 5,132,833 and FR-A-2 391 612, the laser beam is diverted, either for analysis or for printing, by means of a dual-position `switch`.
However such prior art devices have the drawback of being structurally complex and unwieldy.